Two 4-year-olds were killed in a fire that tore through a Far Rockaway home and injured three others just before midnight on April 19, 2014, police said. Photo Credit: Charles Eckert

An investigation is underway to determine how long it took an ambulance to arrive at a Far Rockaway house fire where two 4-year-old children died in a home without a working smoke detector, FDNY officials said Monday.

"We're investigating whether there was a delay at the dispatch and if so, why?" said Frank Dwyer, an FDNY spokesman.

Dwyer said the fire was reported at 11:51 p.m. Saturday and firetrucks arrived at 11:56 p.m. He said it is FDNY protocol to call an ambulance when a fire has been confirmed.

The Easter weekend blaze, which started in a basement apartment, was caused when "the children were playing with a lighter," Dwyer said.

The timeline investigation will determine when the FDNY ambulance was dispatched and when it arrived at the fire, Dwyer said.

One neighbor told Newsday that they watched first responders trying to revive the two children for almost half an hour before they were taken to the hospital. Jai'Launi Tinglin and his half-sister, Aniya Tinglin, were pronounced dead at St. John's Episcopal Hospital, the only hospital on the peninsula.

Jai'Launi was pronounced dead at 1:53 a.m. Sunday and Aniya was pronounced dead at 2:20 a.m., according to hospital officials.

"The smoke detector was nonoperational and unfortunately there were fatalities," Dwyer said. According to the National Fire Protection Association, the risk of dying in reported home fires is cut in half when there are working smoke alarms.

NYPD officers said the children suffered from smoke inhalation. An official cause of death has not been determined by the medical examiner's office pending several test results, spokeswoman Julie Bolcer said.